Field of the Invention
The present invention relates to a chip package and formation method thereof, and in particular relates to a chip package having a through substrate hole and formation method thereof.
Description of the Related Art
Recently, conducting structures (such as TSVs) perpendicular to a surface of a package substrate are commonly being formed in chip packages to form a conducting path along a vertical direction. As a result, space may be employed more effectively, such that the size of the chip package is further shrunk, which helps to improve performance of the chip package.
Typically, a conducting layer is formed on a sidewall of a hole perpendicular to a surface of a package substrate. However, the formed conducting layer may suffer from problems such as cracking or high stress at a bottom corner in the hole, such that the performance of the chip package is affected. In addition, in the conventional chip packaging technique, a complex patterning process needs to be applied, such that a plurality of photoresist application processes, patterning processes, and photoresist stripping processes need to be performed, increasing fabrication cost and time.
In addition, the conducting structure perpendicular to the surface of the package substrate is typically formed in a through substrate hole. The through substrate hole may not only be filled with a conducting material, but many other material stacking layers may also be formed therein. However, during the deposition process of these material stacking layers, these layers are usually also formed on the surface of the substrate outside of the hole. Thus, a following patterning process (usually including an etching process) often needs to be performed to remove undesired material stacking layers on the surface of the substrate. Not only is fabrication cost and time increased, but also, due to the additional patterning process, the elements or structures already formed on the surface of the substrate are at risk of being damaged.
Therefore, a chip packaging technique capable of reducing or resolving the problems mentioned above is desired.